Ok, here are some suggestions for you:
Verse 1, line 2: 'setting off for/heading to/bound for/for/heading towards/en route to New York'
Verse 2, lines 3 + 4: the translation here for me strays from the Spanish...
'the one to blame/the one whose fault it was... Was the captain who got drunk'
Verse 5, line 3: in the context of boats etc 'to raise the flag' is used
Verse 6, lines 1 + 2: 'I want to look from the mainmast'
Verse 6, lines 3 + 4: I think you can say 'in port' but I think 'at port' is more commonly used

I'm happy to help
I suppose you could say 'the guilty one was the captain' if you want to be less literal. You could also say 'the one at fault was the captain'
Just noticed one more thing:
Verse 5, line 4 + Verse 9, line 4: 'from the highest mast of your Brigatine'

In Spanish also, for smaller ones, or if it says "la nave". Still it is a boat, not a person, and if you say 'she' the readers will think it refers to his girl friend, the one he wants to see "from the mainmast".

Well, I think if you translate the first stanza like Valeriu suggested, but with "She" instead of "It", then it will still clearly refer to a sailboat.
But do as you please... My knowledge in Spanish is much much too poor to give any general advice in translation matters. Good luck!

It is not my translation, I just suggested the change, and Vale agreed with me.
There is somethiig else:
The interpretation of the first stanza is wrong: "He left Jamaica..... on a sailboat", seems to indicate that somebody (he) left Jamaica when, actually, it was the sailboat. The verse should say, simply, "a boat", not "on a boat".
But, again, it is not my translation, and we don't edit somebody else's work.

(The translation was submitted in 2012, the author may not read all this).

If the case may be that he would never get to read the comments, then, after a few months from now, I guess, someone should make an updated translation. BUT he hasn't logged in for just 2 months, I've been away for more than that, and I happened to have crossed paths with him before, I suggested a few tweaks in a translation of his and he was very receptive, it was great, and also, he's a moderator, after all, he will probably be back soon =]